ICOA1687: DIGITAL RECORDING AND NON DESTRUCTIVE INVESTIGATION OF NYATAPOLA TEMPLE AFTER GORKHA EARTHQUAKE 2015 Subtheme 03: Protecting and Interpreting Cultural Heritage in the Age of Digital Empowerment Session 3: Application of Digital Technology in Disaster Management Practices Location: Silver Oak 2, India Habitat Centre Time: December 14, 2017, 11:15 – 11:30 Author: S. Shrestha, M. Reina Ortiz, M. Gutland, I. M. Morris, R. Napolitano, M. Santana Quintero, J. Erochko, S. Kawan Dr. Sujan Shrestha is a post doctorate fellow at Carleton University. He had obtained his PhD from Sapienza University, Rome in 2015 and since then working in the heritage sector of Kathmandu Valley with UNESCO Kathmandu Office and Department of Archaeology, Nepal. Abstracts: As a result of the Gorkha earthquake in Nepal on April 25, 2015 and the aftershock that followed on May 12, a large number of heritage structures in Nepal were destroyed and significantly damaged. In particular, the seven monument zones of the Kathmandu Valley World Heritage Site suffered extensive damage. Out of 195 surveyed monuments, 38 have completely collapsed and 157 were partially damaged (DoA, 2015). This paper focuses on one of the areas with the highest heritage value, the historic city of Bhaktapur. It is recognized as a UNESCO World Heritage Site (WHS) and contains many structures of significant cultural and religious importance for the population of the Kathmandu valley. The understanding of these historical structures is principal for the reconstruction and maintenance of the heritage value of the area. In order to achieve this objective, an interdisciplinary collaboration between local experts, engineers and architects is proposed to understand the traditional construction technology and physical response to the earthquake. This paper develops the study of the Nyatapola Temple in detail. The documentation and evaluation of this temple is achieved only from non- destructive techniques: laser scanning, terrestrial and aerial photogrammetry, geo-radar and micro-tremor dynamic analysis. The purpose of this study is to form the basis for a structural analysis to assess the anticipated future seismic performance of the Nyatapola Temple. The use of digital technology aims to shed light on the structural behaviour of the temple and its response to an earthquake. The particular interest in the composition of the plinth and its articulation with the superior hybrid structure has the objective of understanding the structural behaviour of the whole for the future structural rehabilitation. Key words: digital workflows, 3D imaging, georadar, photogrammetry, risk preparedness ICOA1687: DIGITAL RECORDING AND NON DESTRUCTIVE INVESTIGATION OF NYATAPOLA TEMPLE AFTER GORKHA EARTHQUAKE 2015 Introduction Natural disasters like fires, earthquakes, flooding, landslides, storms and hurricanes are among the major causes of loss and damage to physical objects and human lives. These disasters result in an irreplaceable loss in the sector of cultural heritage by damaging the artistic and cultural assets (Taboroff, 2000). The loss to cultural heritage due to disaster further increases in the phase of restoration if proper documentation and information is not available of the damaged heritage structure. Hence, proper documentation and management of information of cultural heritage is important in every heritage conservation project. Likewisely, activities to conserve cultural heritage should persist in a long-run, even after the intervention is completed. This is done through one of many processesses including: documenting and recording site through traditional as well as advanced technologies (Hassini, 2015). Information obtained from the recording process provides the basis for monitoring, management and routine maintenance of a historic site and facilitates the transmission of knowledge about the heritage places to future generations. Additionally, the International Charter for the Conservation and Restoration of Monuments and Sites (The Venice Charter, 1964) in Article 16 states “In all works of preservation, restoration or excavation, there should always be precise documentation in the form of analytical and critical reports, illustrated with drawings and photographs. Every stage of the work of clearing, consolidation, rearrangement, and integration, as well as technical and formal features identified during the course of the work, should be included. Recently, the Gorkha earthquake of magnitude 7.8 (USGS, 2015) severely damaged cultural heritage structures in Nepal. According to a survey report by Department of Archaeology, 745 monuments within twenty districts of the Kathmandu Valley and out of Kathmandu Valley were damaged by the earthquake (DoA, 2015). As per record, 133 monuments were totally collapsed, 97 monuments partially collapsed and 515 suffered partial damage. In Kathmandu Valley, 447 monuments were affected by the earthquake and out of which, 83 monuments were totally collapsed to the base (DoA, 2015). In this regard, the use of digital technologies in data acquisition and recording and documentation of damaged and survived monuments could be very substantial. In particular, the study location, Bhaktapur Durbar Square is a recognized UNESCO World Heritage Site (WHS) containing many structures of significant cultural and religious importance to the people of the Kathmandu Valley. Damage mapping of the heritage structure after the Gorkha Earthquake 2015, within the Bhaktapur Durbar Square monument zone, is shown Fig.1. Sustainable reconstruction and restoration of these heritage structures are critical to maintaining and restoring their outstanding value. To achieve this goal, it is important to work with local experts, engineers, and architects to understand the traditional construction techniques and existing condition of these structures. This study includes the recording and documentation of representative buildings in the historic city of Bhaktapur using non-destructive methods. Fig.1- Damage mapping of monuments in Bhaktapur Durbar Square WHS (Source: Department of Archaeology, Nepal) The scope and objective of the present work include: to record the representative historic structure of Bhaktapur DurbarSquare after the disaster situation; to understand and implement of recording techniques to quickly capture the current conditions of heritage structure of Kathmandu Valley; to capacity buildup in the documentation and recording of historic monuments in accordance with the guidelines and standards, through on-site training to local professional during fieldwork; use of the nondestructive technique to understand the sub-surfacemorphology of the structural elements. Case Study Site: Nyatapola Temple in Taumadhi Square Nyatapola temple, located on the northern side of Taumadhi Square, is one of the finest examples of Newari Architecture built in 1701/1702 A.D by the contemporary king of Bhaktapur King Bhupatindra Malla. The temple is dedicated to Goddess Siddhilaxmi which represents prosperity and good fortune and also represents the Goddess of war. It is believed that temple was built to calm down the destructive avatar of the Bhairaba Temple, which is situated in the east south of the Nayatapola temple. This is the only temple that is named after its architecture rather than named after its deities inside the temple whereas in most of the monuments of Kathmandu Valley are named after its deities inside the monument (Shrestha, 2005). In Newari language, nyata means five and polamean roof (tier). In this way, the temple is named for its external architecture which simply means the five-tier temple. It is the tallest tiered temple in Nepal built with fire burn bricks and timber, which stands on five huge external exposed plinths. There were several earthquakes with magnitude greater than M6.0, that shook the Kathmandu Valley in last 300 years. Among them, great Nepal Bihar earthquake of Magnitude M8.0 in 1934AD, and Gorkha Earthquake of Magnitude M7.8 in 2015 are the major ones.1. During these earthquake events, it was observed that Nyatapola temple experienced minor damages in the upper tier, but surrounding monuments, e.g. Bhairab Temple collapsed completely during the 1934 AD. In this regard, Nyatapola could be taken as one of the finest examples of traditional construction technology, both from architectural as well as structural stability perspectives, due to its resistance to powerful earthquakes from past 300 years. Digital documentation techniques and data acquisition Recording of the proposed monument was divided into two phases: field work and post-processing work. Fieldwork was carried out duringmid-February 2017 for the two weeks of duration. Digital workflow used for the case study is presented in Figure 2. The digital documentation of the Nyatapola Temple in Taumadhi Square has been carried out using different techniques like Electronic Distance Measurement (EDM), terrestrial and aerial Photogrammetry, Laser Scanning, Record Photography and Hand Measurements etc. Different advanced digital recording tools such as Total Station, DSLR Camera, Laser scanner, Drone, and Georadar were used for the recording of surface and sub-surface data of the structure (Fig.3). Terretrial Photogrammetry Setup Local co-ordiante Aerial Photogrammetry Registered 2D and 3D system of the site 3D scanning Point Cloud CAD Model Hand mesurement Fig.2- Digital workflow used for the acquisition of data Set up the local coordinate system: Leica Geosystem TS06 Total Station was